GB Patent No. 2273065 describes a hand operated pump which can be connected to a liquid dispensing apparatus with the purpose of supplying air under pressure to a liquid source such as a pen with a nib of absorbent material. The hand pump described in that patent is suitable for use with various forms of liquid dispensing apparatus.
The hand operated pump described in GB 2273065 comprises a bulb of flexible material formed with an open ended neck which locates over the inlet end of the liquid dispensing apparatus. Air enters the bulb via a nozzle in the liquid dispensing apparatus. When the liquid source has been positioned adjacent the nozzle, the flexible bulb is squeezed and the air pushed out onto and over the liquid source directed by the nozzle. When the bulb is released, air is again drawn up through the nozzle of the liquid dispensing apparatus and into the bulb.
An improvement to the pump of GB2273065 is described in GB2357809. In this arrangement, a separate air inlet is provided. This prevents ink being drawn in back through the nozzle, which may otherwise cause large globules of liquid to be dispensed onto the user's substrate.
A disadvantage of the pumps described in GB2357809 is that a relatively high pressure is required in order to obtain sufficient air flow through the nozzle and over the nib to give the desired effect on the apparatus in use. Consequently, the minimum size of the hand-pump is limited which can prevent effective use of the apparatus by young children whose hands are too small to be able to hold and squeeze the hand-pump with sufficient force to provide suitable airflow over the nib. Furthermore, the limitation in the minimum size of the hand-pump provides an apparatus that can appear ungainly and impractical to some potential users.
These problems are alleviated by the provision of a nozzle with an angled opening in accordance with the present invention.